Detachable hammer head for rotary beaters



March 4, 1952 A. J. ROUBAL DETACHABLE HAMMER HEAD FOR ROTARY BEATERS Filed June 14, 1951 Patented Mar. 4, 1952 DETACHABLE HAMMER HEAD YFOR ROTARY BEATERS Alexander J. Roubal, Milwaukee, 'Wis., assignor to Allis-Chalmers .Manufacturing Company,

Milwaukee, Wis.

Application June 14, 1951, Serial No. 231,601

This invention relates to hammer mills and more Specifically to a renewable hammer element for the same.

Hammer mills having a rotor with a number of hammer arms pivotally mounted on the rotor with each pair of such arms having renewable hammer elements detachably secured thereto are well known. In such mills it is advantageous to have hammer elements of the type which are reversible so that a new breaking edge, on the same hammer element, may be presented when one breaking edge has become worn.

It is an object of the present invention to provide a new and improved detachable hammer elementof the type which is reversible end for end about an axis radial to the rotor shaft, and which may be additionally reversible about an axis parallel to the rotor shaft, and which may be detached from the hammer arms, to allow such reversals, without dismantling the hammer arms from the rotor.

. The invention having the above and still further objects and advantages will appear more fully from this specification and the accompanying drawing in which:

Fig. 1 is a vertical sectional view through a hammer mill casing showing a series of hammer arms with removable hammers mounted thereon;

Fig. 2 is an end view of a hammer assembly including a portion of a hammer arm and locking means for fastening the hammer to the hammer arms;

Fig. 3 is a partial longitudinal sectional view taken on line 1IIIII of Fig. 2;

Fig. 4 is the same end view shown .in .Fig. 2 except that the hammer arm and locking means are omitted;

Fig. 5 is a cross sectional view taken on line VV of Fig. 3;

Fig. 6 is a cross sectional view taken on line VIVI of Fig. v3 except that the hammer arm is omitted;

Fig. 7 is a perspective view to an enlarged scale of elements comprising the locking means shown in Figs. 2 and 3;

Fig. 8 is a partial longitudinal sectional view of a hammer assembly embodying a modifiedform of hammer and locking means therefor;

Fig. 9 is an end view of the hammer assembly shown in Fig. 8;

Fig. 10 is a cross sectional view taken on line X-X of Fig. 8;

Fig. 11 'is a partial longitudinal section of the hammer shown in Fig. 8 but is shown equipped with a modified form of locking means; and

12 Claims. (Cl. 241197) Fig. '12 is a cross sectional 'view taken on line YI-L-XII of Fig. 11.

Referring more particularly to the drawing, Fig. '1 shows a rotary hammer mill which consists essentially of a series of rotatable elements which are located within a, housing or casing 5. A main shaft 6 is rotatably mounted in bearings (not shown) supported by side walls of casing 5 and has a suspension member or disk 1 fixed thereto. Disk 1 is provided with spaced openings in which pins 8 are mounted and secured as by cotter pins. Pins 8 are arranged parallel to each other and pivotally mounted on each pin is a pair of hammer arms 9 which may be respectively mounted thereon a hammer II]. It "is the specific structure of hammers 10 to which the present invention relates but such structure is only diagrammatically shown in Fig. 1.

Hammermills of the type referred to herein are usualy provided with removable casing portions soth'at'the interior of the mill may be inspected, repairs made and worn hammers replaced. A demountable attached casing portion H, which forms 'nopart of the present invention, is shown' in Fig. 1, by way of example, in the upper right hand quadrant of easing 5.

Hammer arms 9 may assume various shapes but each arm is herein illustrated as having a neck portion of narrow width and a head portion I! of somewhat wider width than the neck portion, forming abutments adjacent the neck portion. Both the head and neck portions are shown as having axially extended portions relative to the hammer arm proper, in a direction parallel to pins 8, but this is merely a matter of design.

Referring to Figs. 2 to 7, hammer Illa is illustrated as a one piece rectangular unit of .cast or welded construction with an inverted, enerally U-shaped cross section and comprising a pair of oppositely facing, spaced, generally rectangular breaker bar portions 24 and 25 and a bridge portion 26 connecting and extending longitudinally between the upper parts of the bar portions. The bar portions 24 and 25 may be considered as having opposed spaced rear surfaces 24' and 25 and spaced impact surfaces 2 and 25". Projecting respectively from the lower edges of rear surfaces 24' and 25' are a pair of longitudinally extending ribs 2.1 which structurally strengthen the hammer. 4

Provided respectively at the ends of harmner [9a are longitudinal channel portions 28 and 29, for respectively receiving the heads of a pair of hammer arms 9, which are formed between the rear surfaces 24 and 25 of the bar portions 24 and 25. Channel portion 29 has an opening through the end surface 39 of the hammer for receiving therethrough the head and neck portions of a hammer arm 9.

Provided intermediate the ends of hammer |9a is an assembly slot 32 which is formed between the rear surfaces 24' and 25 of the bar portions 24 and 25 for receiving the head and neck portions of a hammer arm 9 from a radial direction opposite bridge portion 26. Channel portion 28 has an opening, communicating longitudinally with assembly slot 32, through which the head and neck portions of a hammer arm 9 in the assembly slot may be received.

Channel portions 28 and 29 are eachprovided with a pair of horizontally opposite, parallel, longitudinally extending ridges, 33 and 34, and the ridges of each pair project respectively from the rear surfaces 24 and 25 of the bar portions 24 and 25. The crests of the respective ridges 33 and 34 in each channel portion 28 and 29 are spaced apart a distance less than the width of the head portion of a hammer arm 9 but greater than the width of the neck portion.

One end of hammer 19a is provided with abutment means 35, which may be a transversely extending wall positioned longitudinally adjacent channel portion 28. Spaced from the other end of hammer [9a by a distance which may be somewhat greater than the axial length of the head portion of a hammer arm 9, for use with which it is designed, is a similar wall or abutment means 39 positioned between assembly slot 32 and channel portion 29.

In effect it is seen that the-spacing between rear surfaces 24 and 25' is slightly greater than the width of the head portion of a hammer arm 9 and the length of ridges 33 are so chosen that there is suflicient open space between the ends of such ridges and abutment means 36 to form assembly slot 32 for receiving the head portion ll of a hammer arm during assembly. Ridges 33 and bridge portion 26 create the effect of a narrower slot, channel portion 28, adjoining assembly slot 32, to accommodate the head portion of a hammer arm 9 with the neck portion of the arm extending between ridges 33. Ridges 34 and bridge portion 26 similarly create the efiect of a slot, channel portion 29, which accommodates the head portion of a hammer arm 9.

When the head portions of a pair of hammer arms 9 are disposed respectively in channel portions 28 and 29, hammer I9a is prevented from being radially displaced by the engagement of ridges 33 and 34 with the hammer arm head portions. Various locking arrangements to limit longitudinal displacement of hammer I9a relative to the head portions of a pair of hammer arms 9 so as to maintain the hammer in an operative position may be devised, and one such arrangement is illustrated herein by way of example. It will be understoodthat some longitudinal play between the hammer and arms may be permitted.

Locking elements for engagement with hammer [9a are shown-in'detail in Fig. '7. One of the elements is a rectangular retainer plate 38 having a centrally mounted threaded stud 39 projecting therefrom. Formed for cooperation with plate 38 is a generally T-shaped plate 49 having lugs 4| projecting perpendicularly from the ends of the horizontal portion of plate 49. Plate 49 has formed therein a centrally located aperture 42 for receiving stud 39.

The right hand end of channel portion 29 is provided with a transverse, generally rectangular retainer slot 43 which is formed between bar portions 24 and 25 and normal to bridge portion 26 in longitudinal proximity to the end of the hammer. In effect, slot 43 is formed by merely eliminating portions of ridges 34 and ribs 21 so as to provide a space of suificient depth, width and thickness to accommodate retainer plate 38. The end portions 34a and 21a of ridges 34 and ribs 21, adjacent and to the right of slot 43, form a cruciform 44, in cross section, which accommodates T-shaped plate 40 such that the lugs 4| of plate 49 are respectively positioned between ridge portions 34a and rib portions 21a.

With the hammer arms 9 in the position shown in Fig. 3, retainer plate 38 is inserted into transverse slot 43 so as to prevent relative longitudinal movement betweenthe hammer and arms. T- shaped plate 49 is inserted into cruciform 44 with threaded stud 39 projecting through aperture 42 of plate 49. Plates 38 and 49 are then fastened together by means of a nut 45 which engages threaded stud 39 and, as lugs 4| of plate 49 engage rib portions 210. in abutting relation, plate 38 is thereby demountably secured in slot 43.

Hammer l9a is of the type in which the impact surfaces 24" and 25" can be selectively reversed so as to permit use of both of the upper longitudinal edgesbefore requiring replacement of the hammer. As the outer leading edges of each hammer wears rapidly, frequent reversals and replacements of the hammers are necessary.

A primary feature of the invention is that hammer 49a may be reversed to present a new leading edge or replaced with another hammer without necessitating the dismounting of hammer arms 9 from disk I. Disassembly of hammer l9a from arms 9 is readily accomplished by first removing the locking assembly (which may be the locking arrangement described above by Way of example), sliding hammer l9a to the left until the head of the left hand hammer arm 9 is in assembly slot 32 and then lifting hammer Ilia. radially away from arms 9. Hammer I9a may then be reversed end for end, so as to present a new leading edge, and again mounted on hammer arms 9, or be replaced with a new hammer, without disconnecting the hammer arms 9 from disk 1.

Figs. 8 to 10 illustrate a modified form of hammer I9b, embodying the invention, which is not only reversible end for end about an axis radial to the rotor shaft 9 but also side for side about an axis parallel to the rotor shaft.

Hammer I91), as illustrated, is a one piece unit of cast or welded construction and comprises a pair of parallel oppositely, facing, spaced, generally rectangular breaker bar portions 59 and 5| which may be considered as having opposed generally parallel spaced rear surfaces 59 and 5| and impact faces 59" and 5|".

Provided respectively at the ends of hammer l9b are longitudinal channel portions 52 and 53 which are formed between the rear surfaces 59' and 5| of bar portions 59 and 5|. Channel portion 53 has an opening through theend surface 54 of hammer MD for receiving therethrough the head and neck portions of a hammer 9.

Provided intermediate the ends and extending transversely through hammer 19b is an assembly slot 55 which is formed between the rear surfaces 59' and 5| of the bar portions 59 and 5| for receiving the head and neck portions of a hammer arm 9 from either radial direction. Channel portion52 has an opening, communicating longitudinally with assembly slot 5, through which the head and neck portions of a hammer arm 9 may be received.

In each of the channel portions 52 and 53 there is provided two pairs of horizontally opposite, vertically spaced ridges 55, 55' and 57, 57 which project from rear surfaces 55' and 5| of bar portions 50 and 5|. The crests of each pair of horizontally opposite ridges are spaced apart a distance less than the width of the head portion of a hammer arm 9 but greater than the width of the neck portion. The two pairs of ridges in each channel portion are spaced Vertically a distance slightly greater than the radial height of the head portion of a hammer arm 9.

The bars 55 and 5| are connected at the .left hand end by wall like abutment means 58 positioned longitudinally adjacent channel portion 52. Spaced from the right hand end of hammer [b by a distance which may be somewhat greater than the axial length of the head portion of a hammer arm 9, for use with which it is designed,

is a similar wall or abutment means 55, positioned between assembly slot 55 and channel portion 53. Parallel strut members 65 and 60, arranged perpendicular to bar portions 59 and and extending longitudinally between assembly slot 55 and abutment means 59, may be provided when additional strength is required and/ or to serve as a mooring for a locking device as will appear hereinafter.

The spacing between rear surfaces 55 and 5| of bar portions 50 and 51 is slightly greater than the width of the headof a hammer arm 9 for use with which it is designed, and the lengths of the.

hammer, which slot is wide and long enough to accommodate the head of a hammer arm 9. will also be seen that the pairs of ridges 56, 56 and 51, 5'! create the effect of two narrower slots, channel portions 52 and 53, with channel portion 52 adjoining assembly slot 55 and channel portion 53 being adjacent the right hand end of hammer lllb. Each of the channel portions 52 and 53 accommodate, respectively, the heads of hammer arms 9 with the neck portions extending in a radial direction between opposed crests of pairs of ridges 56 and 51 or in the opposite radial direction between opposed crests of pairs of ridges 55 and 57'.

Various locking arrangements to prevent longitudinal displacement of hammer [Db relative to hammer arms 9 may be devised and one such arrangement is shown in Fig. 8. In this illustration strut members 68 and at are utilized as a mcoring for a locking assembly comprising a plate 5| having a generally L-shaped cross section and a plate 62 having a generally crank shaped cross section. With the hammer arms 9 in the position shown in Fig. 8, plate 6| is positioned so that one portion abuts thehead portion of hammer arm 9 and the portion normal thereto abutsxthe lowerside of strut member .60. Plate 62 .is then positioned so that its parallel portions respectively abut plate El and the upper side of strut member 60. The .plates have aligned holes for receiving a threaded bolt 53 which is engaged by a nut.

Disassembly of hammer lflb from .arms .9 is readily accomplished .by first removing the looking assembly, sliding hammer I02) to the left until the head of the left hand hammerarm .9 is in assembly slot 55 and then lifting the hammer radially away from arms 9. Hammer Hlb .may then be reversed end for end or side for side so as to present any one of the four edges as a leading edge, and again be'mounted on hammer arms 9 without disconnecting the arms from disk 1.

Figs. 11 and 12 illustrate a hammer lflc which is substantially the same as hammer IOb except that it is adapted to cooperate with a modified form of locking means.

The locking means illustrated comprises 'a threaded bolt 1!! which extends through a hole in bar portions 500 and 510 that is positioned .to the right of the longitudinal space. occupied by the head portion of the left hand hammer arm 9. Recesses may be provided in the outer surfaces of bars 50c'and 510 to accommodate, respectively,

the head of bolt Ill and a nut 1 l. Bolt lflperforms the same function in this instance as the looking means illustrated and described in connection with hammer lflb.

While specific apparatus is described and illustrated herein, it will be understood that the present invention includes such modifications and equivalents as may readily occur to persons skilled in the art to which it appertains, within the scope of the appended claims.

It is claimed and desired to secure by Letters Patent:

1. A hammer for a rotary impact breaker of the type which has a pair of parallel, radially extending hammer arms each having at the radially outer end thereof an enlarged head portion and an adjacent relatively narrow neck portion, said hammer comprising: a pair of elongated, spaced, generally'rectangular breaker bar portions having oppositely facing impact surfaces and rear surfaces; said .rear surfaces forming therebetween, adjacent one end of said hammer, a first longitudinally extending channel portion having an end opening for receiving the head and neck portions of one of said arms "longitudinally through said one end of said hammer; said rear surfaces forming therebetween and intermediate the ends of said bar portions an assembly slot for receiving the head and neck portions of one of said arms from a radial direction; said rear surfaces forming therebetween, at the end of said hammer opposite said first channel portion, a second longitudinally extending channel portion which communicates with said assembly slot to allow the head and .neck portions of one of said arms in said slot to enter said second channel portion; and at least two longitudinally extending ridges in each of said channel portions projecting respectively from said rear surfaces of said bar portions, the crests of saidridges being spaced transversely apart a distance less than the width of the head portion of one of said arms but greater than the width of said neck portion.

2. The combination of claim 1 including two wall like abutment means for respective engagement with the head portions of said arms, one of said abutment meanszbeing positioned at one end of said hammer adjacent said second channel portion and the second of said abutment means being positioned between said assembly slot and said first channel portion.

3. A hammer for a rotary impact breaker of the type which has a pair of parallel, radially extending hammer arms each having at the radially outer end thereof an enlarged head portion and an adjacent relatively narrow neck portion, said hammer comprising: a pair of elongated, spaced, generally rectangular breaker bar portions having oppositely facing impact surfaces and rear surfaces; said rear surfaces forming therebetween, adjacent one end of said hammer, a first longitudinally extending channel portion having an end opening for receiving the head and neck portions of one of said arms longitudinally through said one end of said hammer; said rear surfaces forming therebetween and interme diate the ends of said bar portions an assembly slot for receiving the head and neck portions of one of said arms from a radial direction; said rear surfaces forming therebetween, at the end of said hammer opposite said first channel portion, a second longitudinally extending channel portion which communicates with said assembly slot to allow the head and neck portions of one of said arms in said slot to enter said second channel portion; at least two longitudinally extending ridges in each of said channels projecting respectively from said rear surfaces of said bar por tions, the crests of said ridges being spaced apart a distance less than the width of the head portion of one of said arms but greater than the width of said neck portion; and said hammer having portions thereof formed to receive locking means for limiting relative longitudinal movement between said hammer and arms when assembled.

4. A hammer for a rotary impact breaker of the type which has a pair of parallel, radially extending hammer arms each having at the radially outer end thereof an enlarged head portion and an adjacent relatively narrow neck portion, comprising: an elongated bar of generally inverted U-shaped cross section having a pair of elongated, spaced, generally rectangular breaker bar portions and a bridge portion connecting and extending longitudinally between the upper parts of said bar portions, said bar portions having oppositely facing impact surfaces and rear surfaces; said rear surfaces forming therebetween, adjacent one end of said hammer, a first longitudinally extending channel portion having an end opening for receiving the head and neck portions of one of said arms longitudinally through said one end of said hammer; said rear surfaces forming therebetween and intermediate the ends of said bar portions an assembly slot for receiving the head and neck portions of one of said arms from a radial direction opposite said bridge portion; said rear surfaces forming therebetwee'n, at the end of said hammer opposite said first channel portion, a second longitudinally extending channel portion which communicates with said assembly slot to allow the head and neck portions of one of said arms in said slot to enter said second channel portion; and at least two longitudinally extending ridges in each of said channel portions projecting respectively from said rear surfaces of said bar portions, the crests of said ridges being spaced apart a distance less than the width of the head portion of one of said 1 arms but greater than the width of said neck portion.

5. The combination of claim 4 including two wall like abutment means for respective engagement with the head portions of said arms. one of said abutment means being positioned at one end of said hammer adjacent said second channel portion and the second of said abutment means being positioned between said assembly slot and said first channel portion.

6. A hammer for a rotary impact breaker of the type which has a pair of parallel, radially extending hammer arms each having at the radially outer end thereof an enlarged head portion and an adjacent relatively narrow neck portion, comprising: an elongated bar of generally inverted U-shaped cross section having a pair of elongated, spaced, generally rectangular breaker bar portions and a bridge portion connecting and extending longitudinally between the upper parts of said bar portions, said bar portions having oppositely facing impact surfaces and rear surfaces; said rear surfaces forming therebetween, adjacent one end of said hammer, a first longitudinally extending channel portion having an endopening for receiving the head and neck portions of one of said arms through said one end of said hammer; said rear surfaces forming therebetween and intermediate the ends of said bar portions an assembly slot for receiving the head and neck portions of one of said arms from a radial direction opposite said bridge portion; said rear surfaces forming therebetween, at the end of said hammer opposite said first channel portion, a second longitudinally extending channel portion which communicates with said assembly slot to allow the head and neck portions of one of said arms in said slot to enter said second channel portion; and at least two longitudinally extending ridges in each of said channel portions projecting respectively from said rear surfaces of said bar portions, the crests of said ridges being spaced apart a distance less than the width of the head portion of one of said arms but greater than the width of said neck portion; and said hammer having portions thereof formed to receive locking means for limiting relative longitudinal movement between said hammer and arms when assembled.

'7. A hammer for a rotary impact breaker of the type which has a pair of parallel, radially extending hammer arms each having at the radially outer end thereof an enlarged head portion and an adjacent relatively narrow neck portion, comprising: an elongated bar of generally inverted U-shaped cross section having a pair of elongated, spaced, generally rectangular breaker bar portions and a bridge portion connecting and extending longitudinally between the upper parts of said bar portions, said bar portions having oppositely facing impact surfaces and rear surfaces; 2. pair of longitudinally extending ribs projecting respectively from the lower edges of said rear surfaces; said rear surfaces forming therebetween, adjacent one end of said hammer, a first longitudinally extending channel portion having an end opening for receiving the head and neck portions of one of said arms longitudinally through said one end of said hammer; said rear surfaces forming therebetween and intermediate the ends of said bar portions an assembly slot for receiving the head and neck portions of one of said arms from a radial direction opposite said bridge portion; said rear surfaces forming therebetween, at the end of said hammer opposite said first channel portion, a second longitudinally extending channel portion which communicates with said assembly slot to allow the head and neck portions of one of said arms in said slot to enter said second channel portion; at least two longitudinally extending ridges in each of said channel portions projecting respectively from said rear surfaces of said bar portions, the crests of said ridges being spaced apart a distance less than the width of the head portion of one of said arms but greater than the width of said neck portion; and a generally rectangular retainer slot formed between said rear surfaces normal to said bridge portion so as to intersect said ribs and ridges in said first channel at a point in proximity to the end of said hammer, said retainer slot having an opening opposite said bridge portion for receiving a generally rectangular looking retainer plate.

8. A hammer for a rotary impact breaker of the type which has a pair of parallel, radially extending hammer arms each having at the radially outer end thereof an enlarged head portion and an adjacent relatively narrow neck portion, comprising: a pair of elongated, spaced,

generally rectangular breaker bar portions hav-' ing oppositely facing impact surfaces and rear surfaces; said rear surfaces forming therebetween, adjacent one end of said hammer, a first longitudinally extending channel portion having an end opening for receiving the head and neck portions of one of said arms longitudinally through said one end of said hammer; said rear surfaces forming therebetween and intermediate the ends of said bar portions an assembly slot for a receiving the head and neck portions of one of said arms from either radial direction; said rear surfaces forming therebetween, at the end of said hammer opposite said first channel portion, a second longitudinally extending channel portion which communicates with said assembly slot to allow the head and neck portions of one of said arms in said slot to enter said second channel portion; and at least two transversely opposite, radially spaced pairs of ridges in each of said channel portions projecting from said rear surfaces of said bar portions, the crests of each pair of transversely opposite ridges being spaced apart a distance less than the width of the head portion of one of said arms but greater than the width of said neck portion and said pairs of said ridges being radially spaced apart a distance slightly greater than the radial height of said head portion.

9. The combination of claim 8 including two wall like abutment means for respective engagement with the head portions of said arms, one of said abutment means being positioned at one end of said hammer adjacent said second channel portion and the second of said abutment means being positioned between said assembly slot and said first channel portion.

10. The combination of claim 9 including a pair of strut members arranged perpendicular to said bar portions and extending between said 19 assembly slot and said second. of said abutment means for receiving locking means for limiting relative longitudinal movement between said hammer and arms when assembled.

11. The combination of claim 9 in which a transversely extending bolt hole is formed in and normal to said bar portions at a point between said assembly slot and said second channel portion for receiving bolt means for limiting relative longitudinal movement between said hammer and arms when assembled.

12. A hammer for a rotary impact breaker of the type which has a pair of parallel, radially extending hammer arms each having at the radially outer end thereof an enlarged head portion and an adjacent relatively narrow neck portion, comprising: a pair of elongated, spaced, generally rectangular breaker bar portions having oppositely facing impact surfaces and rear surfaces; said rear surfaces forming therebetween, adjacent one end of said hammer, a first longitudinally extending channel portion having an end opening for receiving the head and neck portions of one of said arms longitudinally through said one end of said hammer; said rear surfaces forming therebetween and intermediate the ends of said bar portions an assembly slot for receiving the head and neck portions of one of said arms from either radial direction; said rear surfaces forming therebetween, at the end of said hammer opposite said first channel portion, a second longitudinally extending channel portion which communicates with said assembly slot to allow the head and neck portions of one of said arms in said slot to enter said second channel portion; at least two transversely opposite, radially spaced pairs of ridges in each of said channel portions projecting respectively from said rear surfaces of said bar portions, the crests of each pair of transversely opposite ridges being spaced apart a distance less than the width of the head portion of one of said arms but greater than the width of said neck portion and said pairs of said ridges being radially spaced apart a distance slightly greater than the radial height of said head portion; and said hammer having portions thereof formed to receive locking means for limiting relative longitudinal movement between said hammer and arms when assembled.

ALEXANDER J. ROUBAL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,212,991 Newhouse Jan. 16, 1917 1,331,968 Tomlinson Feb. 24, 1920 2,152,332 Smith Mar. 28, 1939 

